<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<div id="app">
    <select v-model="selected">
        <option>html</option>
        <option value="js">js</option>
        <option>css</option>
    </select>
    <p>选择的项是：{{ selected }}</p>
</div>
<script src="https://unpkg.com/vue/dist/vue.min.js"></script>
<script>
    var app = new Vue({
        el:'#app',
        data:{
            selected:'html'
        }
    })
</script>
</body>
</html>